You'll notice
Sessions can now run with all built-in tools disabled, and plugins are blocked from adding tools back in that mode
What
When --allowedTools is given but doesn't match any known built-in tool, Claude Code now recognizes this as a session with built-in tools entirely disabled, and passes that state through its permission logic. Plugins are explicitly blocked from registering any of their own tools in that case.
Why
This closes a gap where a session set up to disable all built-in tools (via --tools "") could still end up with tools available if a plugin added its own, ensuring the restriction is fully enforced.